Method for riveting or piercing and a device for carrying out the method

Abstract

The method according to the invention for riveting, or self-piercing, by means of a riveting or self-piercing device ( 8 ), having a male die ( 3 ) guided by a pick-up device ( 4 ), both of which in each case can be moved towards a female die ( 5 ) and/or a workpiece ( 6 ), wherein the female die ( 5 ) and riveting or self-piercing device ( 8 ) will be connected to one another via a counterforce structure ( 9 ). The relative movement between the pick-up device ( 4 ) and the counterforce structure ( 9 ) is measured by a first sensor ( 1 ), and the relative movement between counterforce structure ( 9 ) and male die ( 3 ) is measured by a second sensor ( 2 ). The depth of the riveting or piercing is adjusted with the aid of the two measured values. The associated device allows fast, accurate detection of the thickness of a workpiece ( 6 ) and precise piercing or riveting with constant predetermined depth irrespective of variations in the quality of the material or other parameters, which can result in deformations of the counterforce structure ( 9 ) during the piercing process.

1. A method of operating on a workpiece ( 6 ) carried on a female die ( 5 ) mounted on one end of a C-shaped counterforce structure ( 9 ) and on which is mounted, at the other end thereof, a device ( 8 ) having a pick-up device ( 4 ), and a male die ( 3 ) guided by the pick-up device ( 4 ), the method comprises the steps of:
 a. measuring relative movement between the counterforce structure ( 9 ) and the pick-up device ( 4 ) with a first sensor ( 1 );  
 b. measuring relative movement between the pick-up device ( 4 ) and the male die ( 3 ) with a second sensor ( 2 ); and  
 c. setting a uniform depth of operation on the workpiece ( 6 ) responsive to the measurements of the first sensor ( 1 ) and the second sensor ( 2 ).  
 
   
   
     2. The method claimed in  claim 1  with the additional step of:
 a. calibrating the setting of the male die ( 3 ) responsive to the measurements of the first sensor ( 1 ) and the second sensor ( 2 ), each of which has recorded a reference value.  
 
   
   
     3. The method claimed in  claim 2  with the additional steps of:
 a. measuring the movement between the counterforce structure ( 9 ) and the pick-up device ( 4 ) by the first sensor ( 1 ) during the operation on the workpiece ( 6 ); and  
 b. controlling the movement of the male die ( 3 ) responsive to the measured movement to set a rivet head projection in the workpiece ( 6 ).  
 
   
   
     4. The method claimed in  claim 3  with the additional step of:
 a. recording measured deformation of the counterforce structure as a quality signal of any one of a selective quality of the counterforce structure ( 9 ), the nature of the workpiece ( 6 ), the rivets and the male and the female dies ( 3  and  5 ), and a process of the operation.  
 
   
   
     5. A method of riveting a workpiece ( 6 ) carried on one end of a C-shaped counterforce structure ( 9 ) above a female die ( 5 ) mounted in the counterforce structure ( 9 ), and on the other end of which a device ( 8 ) is connected, the device ( 8 ) has a pick-up device ( 4 ) and a male die ( 3 ) guided by the pick-up device ( 4 ) and to co-act with the female die ( 5 ), the method comprising the steps of:
 a. applying a force on the workpiece ( 6 );  
 b. measuring relative movement between the counterforce structure ( 9 ) and the pick-up device ( 4 ) with a first sensor ( 1 );  
 c. measuring a single relative movement, selectively, between the pick-up device ( 4 ) and the male die ( 3 ), and the male die ( 3 ) and the counterforce structure ( 9 ) with a second sensor ( 2 ); and  
 d. adjusting the depth of the riveting to a predetermined value responsive to the measured values of the first sensor ( 1 ) and the second sensor ( 2 ).  
 
   
   
     6. The method claimed in  claim 5  with the additional step of:
 a. calibrating setting of the male die ( 3 ) responsive to the measurements of the first sensor ( 1 ) and the second sensor ( 2 ), each of which has recorded a reference value.  
 
   
   
     7. A method of riveting a workpiece ( 6 ) with a rivet having a rivet head that projects upwardly from the workpiece ( 6 ) that is carried on one end of a C-shaped counterforce structure ( 9 ) above a female die ( 5 ) mounted in the counterforce structure ( 9 ) and on the other end of which a device ( 8 ) is connected, the device ( 8 ) has a pick-up device ( 4 ) and a male die ( 3 ) guided by the pick-up device ( 4 ) and to co-act with the female die ( 5 ), the method comprising the steps of:
 a. applying a force on the workpiece ( 6 );  
 b. measuring relative movement between the counterforce structure ( 9 ) and the pick-up device ( 4 ) with a first sensor ( 1 );  
 c. measuring a single relative movement, selectively, between the pick-up device ( 4 ) and the male die ( 3 ), and the male die ( 3 ) and the counterforce structure ( 9 ) with a second sensor ( 2 ); and  
 d. adjusting the height of the projection of the rivet head to a predetermined value responsive to measured values of the first sensor ( 1 ) and the second sensor ( 2 ).  
 
   
   
     8. The method claimed in  claim 7  with the additional step of:
 a. calibrating the setting of the male die ( 3 ) responsive to the measurement of the first sensor ( 1 ) and the second sensor ( 2 ), each of which has recorded a reference value.  
 
   
   
     9. The method claimed in  claim 8  with the additional steps of:
 a. measuring the movement between the counterforce structure ( 9 ) and the pick-up device ( 4 ) by the first sensor ( 1 ) during the riveting of the workpiece ( 6 ); and  
 b. controlling movement of the male die ( 3 ) responsive to the measured movement to set a rivet head projection in the workpiece ( 6 ).  
 
   
   
     10. The method claimed in  claim 9  with the additional step of:
 a. recording measured deformation of the counterforce structure ( 9 ) as a quality signal of any one of a selective quality of the counterforce structure ( 9 ), the nature of the workpiece, the rivets and the male and the female dies ( 3  and  5 ) and a process of the operation.  
 
   
   
     11. A combination wherein an operating device ( 8 ) is mounted on one end of a C-shaped counterforce structure ( 9 ) on which the other end has mounted thereon a female die ( 5 ) which carries a workpiece ( 6 ), and comprising:
 a. a pick-up device ( 4 ) moveable in a direction of the female die ( 5 );  
 b. a male die ( 3 ) guided by the pick-up device ( 4 ) to be moveable in the direction of the female die ( 5 );  
 c. a first sensor ( 1 ) to measure relative movement between the pick-up device ( 4 ) and the counterforce structure ( 9 ); and  
 d. a second sensor ( 2 ) selectively to measure relative movement between the pick-up device ( 4 ) and the male die ( 3 ) and between the male die ( 3 ) and the counterforce structure ( 9 ).  
 
   
   
     12. The combination claimed in  claim 11  wherein:
 a. the first sensor ( 1 ) defines a digital counter.  
 
   
   
     13. The combination claimed in  claim 12  wherein:
 a. a monitoring unit ( 7 ) measures values of the first sensor ( 1 ) and the second sensor ( 2 ) to calculate and record deformation of the counterforce structure ( 9 ) from the measured values of the first sensor ( 1 ) and the second sensor ( 2 ).  
 
   
   
     14. A combination wherein a riveting device ( 8 ) is mounted on one end of a C-shaped counterforce structure ( 9 ) on which the other end has mounted thereon a female die ( 5 ) which carries a workpiece ( 6 ), and comprising:
 a. a pick-up device ( 4 ) moveable in a direction of the female die ( 5 );  
 b. a male die ( 3 ) guided by the pick-up device ( 4 ) to be moveable in the direction of the female die ( 5 );  
 c. a first sensor ( 1 ) to measure relative movement between the pick-up device ( 4 ) and the counterforce structure ( 9 ); and  
 d. a second sensor ( 2 ) selectively to measure relative movement between the pick-up device ( 4 ) and the male die ( 3 ) and between the male die ( 3 ) and the counterforce structure ( 9 ).  
 
   
   
     15. The combination claimed in  claim 14  wherein:
 a. the first sensor ( 1 ) defines a digital counter.  
 
   
   
     16. The combination claimed in  claim 15  wherein:
 a. a monitoring unit ( 7 ) measures values of the first sensor ( 1 ) and the second sensor ( 2 ) to calculate and record deformation of the counterforce structure ( 9 ) from the measured values of the first sensor ( 1 ) and the second sensor ( 2 ).  
 
   
   
     17. A combination wherein a piercing device ( 8 ) is mounted on one end of a C-shaped counterforce structure ( 9 ) on which the other end has mounted thereon a female die ( 5 ) which carries a workpiece ( 6 ), and comprising:
 a. a pick-up device ( 4 ) moveable in a direction of the female die ( 5 );  
 b. a male die ( 3 ) guided by the pick-up device ( 4 ) to be moveable in the direction of the female die ( 5 );  
 c. a first sensor ( 1 ) to measure relative movement between the pick-up device ( 4 ) and the counterforce structure ( 9 ); and  
 d. a second sensor ( 2 ) selectively to measure relative movement between the pick-up device ( 4 ) and the male die ( 3 ) and between the male die ( 3 ) and the counterforce structure ( 9 ).  
 
   
   
     18. The combination claimed in  claim 17  wherein:
 a. the first sensor ( 1 ) defines a digital counter.  
 
   
   
     19. The combination claimed in  claim 18  wherein:
 a. a monitoring unit ( 7 ) measures values of the first sensor ( 1 ) and the second sensor ( 2 ) to calculate and record deformation of the counterforce structure ( 9 ) from the measured values of the first sensor ( 1 ) and the second sensor ( 2 ).  
 
   
   
     20. A combination wherein a self-piercing device ( 8 ) is mounted on one end of a C-shaped counterforce structure ( 9 ) on which the other end has mounted thereon a female die ( 5 ) which carries a workpiece ( 6 ), and comprising:
 a. a pick-up device ( 4 ) moveable in a direction of the female die ( 5 );  
 b. a male die ( 3 ) guided by the pick-up device ( 4 ) to be moveable in the direction of the female die ( 5 );  
 c. a first sensor ( 1 ) to measure relative movement between the pick-up device ( 4 ) and the counterforce structure ( 9 ); and  
 d. a second sensor ( 2 ) selectively to measure relative movement between the pick-up device ( 4 ) and the male die ( 3 ) and between the male die ( 3 ) and the counterforce structure ( 9 ).  
 
   
   
     21. The combination claimed in  claim 20  wherein:
 a. the first sensor ( 1 ) defines a digital counter.  
 
   
   
     22. The combination claimed in  claim 21  wherein;
 a. a monitoring unit ( 7 ) measures values of the first sensor ( 1 ) and the second sensor ( 2 ) to calculate and record deformation of the counterforce structure ( 9 ) from the measured values of the first sensor ( 1 ) and the second sensor ( 2 ).  
 
   
   
     23. A method of piercing a workpiece ( 6 ) carried on a C-shaped counterforce structure ( 9 ) comprising the steps of:
 a. deforming a C-shaped counterforce structure ( 9 ) with a sufficiently large force, while the counterforce structure ( 9 ) carries the workpiece ( 6 );  
 b. measuring the deformation of the C-shaped counterforce structure; and  
 c. correcting the force of the piercing to a predetermined amount to produce a uniform result responsive to the extent of the deformation,  
 wherein movement between the counterforce structure ( 9 ) and a pickup device ( 4 ) by a first sensor ( 1 ) during the piercing of the workpiece ( 6 ) is measured, and movement of a male die ( 3 ) is controlled responsive to the measured movement to set a rivet head projection in the workpiece ( 6 ).  
 
   
   
     24. The method claimed in  claim 23 , with the additional step of:
 a. recording the measured deformation of the counterforce structure ( 9 ) as a quality signal of any one of a selective quality of the counterforce structure ( 9 ), the nature of the workpiece ( 6 ), rivets and the male and female dies ( 3  and  5 ), and a process of the piercing.